This structure came into use in 373 during the reign of the Byzantine Emperor Valens. It was the final element in an extensive series of tunnels and aqueduct bridges, constructed from the mid-4th century and extending some 250km into northern Thrace, which brought water to the city.Originally nearly one kilometre in length and up to 29 metres high, the structure was kept in repair throughout history and was in use until the late 19th century.View of the north side of the aqueduct, looking towards Atatürk Bulvarı, on the other side of which can be seen part of the Medrese of Gazanfer Ağa, which now houses the Museum of Cartoons and Humour.______________________________________________